From 4809857318833bb2cc2505afe3ee62b2dbca5a3e Mon Sep 17 00:00:00 2001
From: mkoch <mkoch@XNPSTER-HP>
Date: Sun, 14 Jan 2024 15:36:52 +0300
Subject: [PATCH] dead code: fixed memory leaks, simplified code for empty
 do/while/if removing, removing of 'else' branch

---
 .../_src/Transformations/dead_code.cpp        | 80 +++++++------------
 1 file changed, 29 insertions(+), 51 deletions(-)

diff --git a/sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp b/sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp
index 9b6411f..01c76f8 100644
--- a/sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp
+++ b/sapfor/experts/Sapfor_2017/_src/Transformations/dead_code.cpp
@@ -10,6 +10,8 @@ using std::string;
 using std::vector;
 using std::set;
 
+#define PRINT_USELESS_STATEMENTS 1
+
 static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instruction* instr,
                                        set<SAPFOR::Argument*>& use, set<SAPFOR::Argument*>& def,
                                        vector<SAPFOR::Argument*>& formal_parameters,
@@ -318,12 +320,6 @@ void removeDeadCode(SgStatement* func,
 {
     SgProgHedrStmt* prog = isSgProgHedrStmt(func);
 
-    if (prog)
-        __spf_print(1, "[analyze %s]\n", prog->name().identifier());
-    else
-        __spf_print(1, "[cannot resolve name of function]\n");
-
-    
     auto cfg = buildCFGforCurrentFunc(func, SAPFOR::CFG_Settings(true, false, false, false, false, false, false), commonBlocks, allFuncs);
 
     if(cfg.size() != 1)
@@ -333,14 +329,14 @@ void removeDeadCode(SgStatement* func,
 
     vector<SAPFOR::Argument*> func_parameters(cfg_pair.first->funcParams.countOfPars, NULL);
 
-    DeadCodeAnalysis* analysis_object = new DeadCodeAnalysis(func_parameters);
+    DeadCodeAnalysis analysis_object(func_parameters);
 
-    analysis_object->fit(cfg_pair.second);
-    analysis_object->analyze();
+    analysis_object.fit(cfg_pair.second);
+    analysis_object.analyze();
 
     set<SgStatement*> useful;
 
-    for (DeadCodeAnalysisNode* byNode : analysis_object->getNodes())
+    for (DeadCodeAnalysisNode* byNode : analysis_object.getNodes())
     {
         const auto& instructions = byNode->getBlock()->getInstructions();
         const auto& statuses = byNode->getResult();
@@ -357,10 +353,7 @@ void removeDeadCode(SgStatement* func,
                 SgStatement* stmt = instructions[i]->getInstruction()->getOperator();
 
                 while(stmt && useful.insert(stmt).second)
-                {
-                    __spf_print(1, "[Useful statement '%s' on line %d]\n", stmt->unparse(), stmt->lineNumber());
                     stmt = stmt->controlParent();
-                }
             }
         }
     }
@@ -372,65 +365,50 @@ void removeDeadCode(SgStatement* func,
         ASSIGN_STAT
     };
 
-    SgStatement* enclosing = st->controlParent();
-    SgStatement* encl_end = enclosing ? enclosing->lastNodeOfStmt() : NULL;
-
     while (st != end)
     {
         SgStatement* next = st->lexNext();
-        SgStatement* parent = NULL;
 
         if (removable.find(st->variant()) != removable.end() && useful.find(st) == useful.end())
         {
-            __spf_print(1, "[Useless statement '%s' on line %d]\n", st->unparse(), st->lineNumber());
+            __spf_print(PRINT_USELESS_STATEMENTS, "[Useless statement '%s' on line %d]\n", st->unparse(), st->lineNumber());
 
-            parent = st->controlParent();
-
-            st->extractStmt()->deleteStmt();
-            st = NULL;
+            st->deleteStmt();
         } 
         else
         {
-            if (st == encl_end)
+            if (isSgControlEndStmt(st))
             {
-                if (enclosing)
+                SgStatement* parent = st->controlParent();
+                SgStatement* parent_end;
+
+                if (parent && (parent_end = parent->lastNodeOfStmt()) && parent_end == st)
                 {
                     bool empty_parent = false;
 
-                    switch (enclosing->variant())
+                    switch (parent->variant())
                     {
-                        case IF_NODE:
-                            empty_parent = 
-                                enclosing->lexNext() == encl_end || // IF THEN ENDIF
-                                    enclosing->lexNext()->variant() == CONTROL_END && 
-                                    enclosing->lexNext()->lexNext() == encl_end; // IF THEN ELSE ENDIF
-                            break;
-                        default:
-                            empty_parent = enclosing->lexNext() == encl_end;
-                            break;
+                    case IF_NODE:
+                        empty_parent =
+                            parent->lexNext() == parent_end || // IF THEN ENDIF
+                            isSgControlEndStmt(parent->lexNext()) &&
+                            parent->lexNext()->lexNext() == parent_end; // IF THEN ELSE ENDIF
+                        break;
+                    default:
+                        empty_parent = parent->lexNext() == parent_end; // DO, WHILE
+                        break;
                     }
 
-                    if(empty_parent)
-                    {
-                        parent = enclosing->controlParent();
-                        enclosing->extractStmt()->deleteStmt();
-                        st->extractStmt()->deleteStmt();
-                        st = NULL;
-                    }
+                    if (empty_parent)
+                        parent->deleteStmt();
+                    else if(isSgIfStmt(parent) && isSgControlEndStmt(parent_end->lexPrev())) // IF with empty ELSE branch
+                        parent_end->deleteStmt();
                 }
-                
             }
         }
 
-        if(!parent)
-            parent = st->controlParent();
-
-        if (parent != enclosing)
-        {
-            enclosing = parent;
-            encl_end = enclosing ? enclosing->lastNodeOfStmt() : NULL;
-        }
-
         st = next;
     }
+
+    deleteCFG(cfg);
 }
\ No newline at end of file